The computer and semiconductor industry requires storage and transportation of memory disks for computer hard drives.
In the storage and transport of memory disks or other wafers hereinafter “substrates”, there is always concern for the possibility of breakage and/or causing damage to the substrates or otherwise interrupting the processing and manufacturing steps. Many types of substrate carriers have spacers or “teeth” extending inwardly from the sidewalls to space the substrates from each other. The teeth generally have a uniform cross-section along their length. Shippers 10 for memory disks typically comprise a cassette 12 or body portion, a top cover 14 and a bottom cover 16 as illustrated in FIG. 7 having portions cut-away. The body portion has opposing side walls 20, 22 and opposing end walls 24, 26. The opposing sidewalls have inwardly facing teeth 30 or spacers to hold the substrates in a vertically positioned and spaced array. The cassette has an open top 32 and open bottom 34 to accommodate cleaning of the carrier and access to the substrates. Endwalls have U-shaped openings 40 to permit access to centrally located apertures in the hard disks. The top cover is configured to cover the open top as well as the U-shaped openings of the endwalls. Such carriers are illustrated in U.S. Pat. Nos. 4,557,382 and 5,253,755. These two patents are incorporated herein by reference.
One difficulty encountered in the use of conventional substrate carriers is that the substrates do not always load perfectly into the slots in the carriers. This is particularly true for hard disk shippers such as illustrated in the '382 and '755 patents. The slots, which are defined by ribs or teeth on the sidewalls, are designed to vertically receive the disks and provide a separation that keeps the disks from contacting each other. The disks, however, sometimes come to rest on top of the teeth that separates the slots and do not fully seat in the slot and can contact adjacent disks. As a result, the disks can be damaged or interfere with processing. A configuration is needed to avoid this problem and minimize cost and expense of modifications of existing tooling to manufacture such a configuration.